Gas-engine



F. D. SHEPHERD.

GAS ENGINE.

APPLICATION FILED SEPT. 12. 1913.

1,318,927. Patented Oct. 14,1919.

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GAS ENGINE. APPLICATION HI .ED sEPT.12. 1918.

Patented Oct. 14, 1919.

7 wwz Z M 6 3 4 22 MM 21 z n z a 88 a I 2 zlw 0 0 2 1% Q 6% N m mz FRANK D. SHEPHERD, OF AURORA, ILLINOIS.

GAS-ENGINE.

Specification of Letters Patent.

Application filed September 12, 1918. Serial No. 253,699.

To all ivkom it may concern:

Be it known that I, FRANK D. SHEPHERD,

of Aurora, in the county of Kane and State of Illinois, have invented certain new and useful Improvements in Gas-Engines, and do hereby .declare that the following is a full, clear, and exact description thereof.

My invention relates'to gas engines, and my object is to provide certain improv ments in the valve mechanism and in the engine head used in connection therewith to the end that injury from high temperatures may be avoided, and efficiency in use and economy in manufacture may be promoted, and to this end my invention cons sts 1n the construction substantially as hereinafter Specified and claimed.

In the drawings Figure 1 is a vertical section of a portion of a gas engine embodying my invention,

Fig. 2 is a top plan view of the engine head, a part of the cover plate for the valve spring housings being broken away,

Fig. 3 is a detail view, partly in side elevation and partly in section of the valve parts shown in Fig. 1.

Fig. 4 is a view like Fig. 1 of another embodiment of my invention.

Fig. 5 is a view similar to Fig. 2, of the engine head of the construction shown in Fig. 4.

Fig. 6 a vertical section bodiment;.

Fig. 7 a detail view of valve parts of still another construction.

Referring to the drawings in detail, 10 designates the detachable head of a multicylinder L-head type of engine, the cylinders of another embeing cast en bloc, but while my invention is speclally advantageous in a multi-cylinder engine, cast en bloc, I contemplate its application to a single cylinder type; or a multicylinder engine not cast en bloc. And my invention is also applicable to a T-head as well as an L-head type of engine, so that by illustrating the L-head type, I do not restrict myself thereto.

Each cylinder has its own valve mechanism, and as all are alike, it will be sufiicient to describe one such mechanism. The valve is a puppet valve having a head 11 that rests on a seat 12 at the bottom of a transverse passage or port 13 in the underside of the engine head 10, that leads to the top of the cylinder, and as usual, it is periodically lifted from its seat bya cam-actuated lifter rod or stem 14. The latter may be integral with the valve head, as shown in Fig. 4; or separate therefrom, as shown in. Figs. 1, 3 and 6, and when separate, I prefer to make lts valve-engaging end convex or crowned, and the surface of the valve head which it engages made flat or plane, as thereby the surfaces coming in contact are materially less than is the case when two'fiat or otherwise similar faces on rod and valvehead are employed, so that the engine makes-f Patented Oct. 14, 1919.

less noise in running; and, again, less clear-' ance need be left, between the actual contacting surfaces of rod and valve head, whenthe'.

valve is on its seat. The lower as well as the top end may be crowned; or if preferred,-

either or both ends may be flat. I also prefer, when the rod or stem is separate from v the valve head, to provide a cavity or recess- 15 in the underside of the valve head, to re-.

ceive the upper end of the lifting rod or.

stem, as thereby the'end of the latter 'is-1- housed and protected,a feature especially desirable with the exhaust valves of large tractor engines since thereby the direct action of the burning or hot exhaust gases on the rod end is avoided. The cavity 15 is enough larger in diameter than the rod or' stem to permit free lateral movement of the valve head in seating so that it is independent of the rod or stem,the construction thus provided really being a floating valve.

which will not leak from improper seating.

On the upper side of the valve head, is a stem 16 that reaches across the and passes through a guide hole 17 which it slidablv fits, and enters a chamber in a housing 18 that is cast integral with the engine head. Within the chamber is an expansive coiled spring 19 that transmits to the valve stem 16, through a head or disk 20. pressure to move the valve to and hold it yieldingly port 13,

upon its seat 12. The disk 20 may be inte- I gral with the valve stem. in which case the latter will be separate from the valve, as shown in Fig. 4; or it may be separate therefrom. as shown in Figs. 1, 3 and 7, and hearing at its central portion on the end of the stem, and without. or with a cavity 21 in its underside to receive the upper end of the stem. On its rim the disk 20 is provided with vertical grooves or notches 20 to allow the passage of air and thus prevent hindrance, from air pressure, to its free movement. The disk, when made as shown in Figs. 1, 3 and 7, is inexpensive to manufacture, as it can be stamped out.

As shown in Fig. 7, the upper valve stem 161 may be separate from both the valve head 11 and the spring-engaging disk.

At. its upper or outer end the spring bears against a disk 22 that is thereby held yieldingly against the outer end wall of the chamber and over a hole 23 in said wall pro vided for the introduction of lubricating oil into the chamber, the face of the disk being ground to assure the gas-tight closing of the oil hole, it being an lmportant characteristic of the spring housing that it shall be closed gas tight to the atmosphere to prevent escape of any gas therefrom which, perchance, might get into the housing chamber. The rim of the disk 22 is also provided with notches or grooves for the ready passage of oil by the disk.

The outer end wall of the spring housing 18 is formed by a removable plate 24 whic preferably is of a size to cover all the housings of the engine head, and is secured thereto by screws 25, a gasket 26 being placed between the plate and the end edges of the housing to make a gas-tight joint.

A very important reason for making the spring housing, or housings integral with the engine head is the opportunity thereby I afforded to water-cool the valve stem where it passes through its guide hole, and also to watercool the housing itself, if that be desired. When the housin is made separate, and screwed into a tireaded hole in the engine head, a double thickness of metal intervenes between the water space, if provided in the head, and the valve stem. By my integral construction the water space 27 in the head 10, can be carried around the valve stem guide, with but a single thin wall 28 intervening, as shown in both Figs. 1, 1 and 6; and as shown in Fig. 1, such Water space can have an extension 29 around the sprin chamber, and thereby water-cool the latter. Or, as shown in Figs. Land 6, the spring housings can be air-cooled, by giving the walls a skeleton form, making them thin for the most part and providing ribs 30, at intervals to receive the holes for the cover attaching screws.

It will be noted that the spring housing has a bottom beneath which the water jacket space extends, so that transmission of heat into the chamber and affecting the spring is guarded against.

The integral construction of head and sprin housings is also advantageous in that it makes for economy of manufacture by saving the necessity for threading the hole and the end of the housing when a screw connection is employed; and cost of con- As will be apparent the form of valve mechanism shown in connection with the engine head of Fig. 1, can be used wlth the head construction shown in Flg. 1- and vice versa.

located, as indicated at 31, in Fig. 1, or at either one side, at either end of the intake port, as indicated at 32, in Fig. 1.

It is important when the engine head has been removed and is to be replaced, that it be accurately restored to its former position, especially with the valves of the construction shown in Figs. 1 and 3, and which are fitted and round into their seats, to assure that the va ves will accurately seat when the head has again been put in place. I accomplish this ,by providing engine head and cylinder block with interlocking pins, or studs, and holes, the pins 33, being for example on the underside of the head, and one at each end thereof, and a hole 34 for each pin being provided in the cylinder block.

As shown in Figs. 1, 3 and 6, the upper valve stem adjacent the head may have a concave fillet 35, in which event a convexly curved cavity 36 to receive it, is provided adjacent the inner end of the stem guiding hole, and a shoulder 37 is formed adjacent said hole to scrape off carbon from the valve stem.

In making my present invention, especially in regard to the cooling feature of the engine head, I have had in view the case of high compression engines in which very high temperatures are produced, and engines using low grades of fuel oil, and to engines of such description my invention is especially applicable.

The surfaces of the various parts within the housing, as well as the inner walls of the latter are plated or covered with some metal or material C, such as copper, which will resist the corrosive action of the gases that after the engine has run some time find their way into the housing. Experience has shown that the parts thus exposed to the action of the gases undergo a deterioration, and I avoid itby the means described.

As shown in Fig. 6 the valve parts are similar to those shown in Fig. 1, but the spring containers 18 are of the skeleton aircooled type of Figs. 4: and 5, but instead of being integral with the engine head, are of the bonnet type 38 with an integral head 39 with a central oil hole 40, instead of the removable cover shown in Figs. 1 and 3, the bonnet having side lugs or ears 41 at its bottom where .it rests on a raised, machined boss 42, on the engine head, a gasket 43 being used to make a gas-tight joint. The boss The spark plug holes may be centrally with the working chamber, an engine head from which projects a housing, a stem reaching from the housing to the valve, a spring within the housing acting on the stem to seat the valve and a Wall integral with the head within which is an opening through which the stem passes from the housing to the valve, the head having a water space reaching to said wall.

2. An internal combustion engine having a puppet valve controlling communication with the working chamber, an engine head from which projects a housing, a stem reaching from the housing to the valve, a spring within the housing acting on the stem to seat the valve and a wall integral with the head within which is an opening through which the stem passes from the housing to the valve, the head havin a water space reaching to said wall, sald wall being a single thickness.

3. An internal combustion engine having a plurality of bonnet-form housings, made en bloc, each with a chamber, and projecting from the engine head, a coil sprlng in the chamber, a puppet valve, a stem reaching from the chamber to the valve acted on by the spring to seat the valve, and a wall integral with the head surrounding the'stem between the chamber and the valve, the engine head having a water space reaching to said wall.

4. The combination of an internal combustion engine, having a valve seat, a puppet valve, an engine head having a housing from the interior of which leads a valve stem guiding hole, a stem that reaches from the valve into said chamber, through said hole, a spring within the chamber acting on said stem to hold the valve to its seat, and a valve lifting rod engaging a surface on the valve within a recess in the valve, a clearance being provided between the sides of said recess.

and the rod.

5. The combination of a gas engine having a valve seat, a puppet valve, an engine head having a housing with a chamber from which leads a valve stem guiding hole, a stem reaching from the valve into said chamber through said hole and a spring within the chamber acting on said stem to hold the valve to its seat, said head having a water space extending beneath the chamber bottom to the wall of said hole, said wall being integral with the head.

In testimony that I claim the foregoing I have hereunto set my hand.

FRANK D. SHEPHERD. 

